The invention relates in general to fuel injection apparatus and, in particular, to a method and apparatus for controlling the spray characteristics of fuel injection apparatus in gas turbine engines. The invention relates especially to a method and apparatus for controlling the spray characteristics to permit fuels of varying grades to be burned efficiently in present gas turbine engine designs.
As a result of the world petroleum situation, the future availability of petroleum products is uncertain and the cost of such products is steadily increasing. In this situation, an engine which can operate efficiently on a variety of fuels has many advantages. Fuels refined to less exacting specifications are less costly than fuels refined to more exacting specifications. The problem of fuel availability is reduced if an engine can operate on a variety of fuels.
Present gas turbine engines have been designed to operate most efficiently with a standard fuel. In general, the fuel injection nozzles of these engines have been optimized for use with a fuel having a specific aromatic content. Fuels having higher aromatic content cannot be burned efficiently in these engines. Higher aromatic content fuels are more viscous so that a given nozzle will not produce the finely atomized spray need for proper combustion. Moreover, the use of a different fuel may produce increased exhaust emissions which will likely impinge on Environmental Protection Agency standards.